Reciprocating switch assembly for distribution panels

ABSTRACT

This invention relates to a device for the distribution of electrical signals from a signal source to the control members of a receiving apparatus. In accordance with the invention, there is provided a plurality of elongated fixed contact strips, each having a plurality of fixed contacts thereon. A first distributing means picks up signals from the program carrier and distributes these signals to a printed circuit board which distributes the signals to the various fixed contacts of the contact strips. A slide-contact member is slidably disposed on each of the contact strips for movement therealong, and have a plurality of slide-contacts which engage corresponding ones of the fixed contacts of the contact strips. In this manner, predetermined ones of the signals from the signal source can be selected and routed to the receiving apparatus by a second distributing means.

United States Patent Hohenberger et al.

[ Oct. 17, 1972 hle; Heinz Knitter, Schubler, both of Germany [73] Assignee: The Bunker-Ramo Corporation,

Oak Brook, Ill.

[22] Filed: Nov. 2, 1970 [2]] Appl. No.: 85,843

[30] Foreign Application Priority Data Bentley ..200/16 A Pipdonzi ..200/16 A Primary Examiner-J. R. Scott Attorney-Frederick M. Arbuck le [57] ABSTRACT This invention relates to a device for the distribution of electrical signals from a signal source to the control members of a receiving apparatus. In accordance with the invention, there is provided a plurality of elongated fixed contact strips, each having a plurality of fixed contacts thereon. A first distributing means picks Oct. 31, 1969 Germany ..P 19 55 020.0 up signals from the program carrier and distributes these signals to a printed circuit board which dis- U-S. Cl. A, R tributes the signals to the various fixed contacts of the CI. ontact strips A siide-contact member is [58] Field of Search ...200/ll D, 11 DA, 16 A, 6 disposed on each of the contact strips for movement 317/101 therealong, and have a plurality of slide-contacts which engage corresponding ones of the fixed contacts [56] References C'ted of the contact strips. In this manner, predetermined UNiTED STATES PATENTS ones of the signals from the signal source can be selected and routed to the receiving apparatus by a 3,476,983 ll/l969 De Robertis 317/101 DH Second distributing means 3,536,865 10/1970 Meyer ..200/11 D 3,502,824 3/1970 Bonacquisti ..200/16 D 7 Claims, 9 Drawing Figures s s e 5e 4 S Q46 Z5 PATENTEDum 17 I972 sum 2 or 5 T KNN w: =m E RECIPROCATING SWITCH ASSEMBLY FOR DISTRIBUTION PANELS BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to a device for the distribution of electrical signals from a signal source to the control members of a receiving apparatus. It is highly desirable in such fields as textile manufacturing that a program source of impulse signals is transmitted in a variety of combinations to the knitting needles of a textile knitting machine. in order to change patterns generated by the knitting machine, it is necessary to alter the electrical impulse signals and apply them to different ones of the knitting needle control members so that anew pattern on the finished product can be created.

2. Description of the prior Art In the past, selectively altering the distribution of control signals from a program source to a receiving apparatus involved complex and time consuming operations of connecting and disconnecting multi-contact plugs at best, and often required shut-down of the receiving apparatus for a considerable length of time in order to permanently wire the system to obtain an altered signal distribution, thereby permitting a different pattern to be generated at the receiving apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for the distribution of electrical signals from a signal source to the control members of a receiving apparatus in which predetermined ones of the source signals are easily and quickly selected for transmission to the receiving apparatus.

lt is a further object of the invention to provide a device of the type indicated above, in whichthe signals from the signal source is distributed to a plurality of contact strips, and a plurality of slide-contact members can be positioned along any one of the contact strips to select a desired signal program.

It is yet another object of this invention to provide a device for the distribution of electrical signals from a signal source to the control members of a receiving apparatus in which a variety of electrical impulse signals are transmitted to at least one contact strip, and a slidecontact member is slidably positioned on the contact strip. in this arrangement, the slide-member is provided with resilient means for selectively disengagingthe mutually engaging contacts of the slide-contact member and the contact strip when the position of the slide-contact member is changed, and to re-engage the mutually opposing contact members at a desired position along the contact strip.

In accordance with a preferred embodiment of the invention, there is provided a plurality of elongated fixed contact strips, each having a plurality of fixed contacts thereon. A first distributing means picks up signals from the program carrier and distributes the signals to a printed circuit board which distributes the signals to the various fixed contacts of the contact strips. A slide-contact member is slidably disposed on each of the contact strips for movement therealong, and positionable in a plurality of positions along the contact strips, the slide-contact member including a plurality of slide-contacts which engage corresponding ones of the fixed contacts of the contact strips. in this manner, the slide-contact member can be positioned along the contact strip to select predetermined ones of the signals from the signal source. The selected signals passing through mutually engaged fixed and slide-contacts are then routed to the receiving apparatus by a second distributing means The invention is shown and described in terms of its applicability to the field of textile pattern devices. However, the distribution panel construction and function is applicable to a variety of other industrial and commercial uses.

For use in conjunction with a textile pattern device, the invention relates to a distribution panel for the distribution of impulse signals which are stored on a multitracked program carrier. By means of a sensing or scanning device, for example by the use of impulsetransducers, selected ones of the impulse source signals are distributed to the distribution panel and transferred selectively to the control members of a knitting machine. In this manner, each of the control members of the receiving apparatus, e.g., the needle control members of a knitting machine, can be selectively operated in parallel with other control members and are controllable in this respect, through manipulations on the distribution panel, by at least two of the impulsetransducers.

The immediately observable advantage of such a distribution system lies in the fact that the program carrier may comprise a relatively small number of tracks in accordance with a predetermined program, and yet by the utilization of the distribution panel in accordance with the invention, control of a number of control members many times greater than the number of tracks on the program carrier is achievable. This has great advantage when utilizing the distribution panel for controlling the actuating devices for the frame of a mechanical jacquard loom or the needles of a knitting machine, in that a simpler programming source is required. With particular reference to the use of the distribution panel in a knitting machine having needles ultimately controllable by means of the sensing or scanning device, the impulse signals stored on the program carrier can be repeated at a high rate to create a single pattern many times during each lateral displacement of the knitting machine frame. This obviates the need for a lengthy program to cycle once for each lateral displacement of the frame. By requiring a simple and shorter repetitive program, the program carrier reader (scanning device), as well as the receiving apparatus, can be designed more economically simple and space-saving in construction.

The preferred embodiment serving as a basis for the description herein comprises a plurality of pulse-transducers which sense the information contained on the program carrier and transmit corresponding electrical signals through a first distributing means to the fixed contacts of a plurality of contact strips extending in a longitudinal direction on the distribution panel. A slide-contact member is slidably disposed above each of the contact strips for selectively engaging the contacts thereon. The contact strips are identical with one another at least in regard to the number of contacts contained in each contact strip.

Each of the slide-contact members have a plurality of slide-contacts which mate with corresponding contacts of the contact strips, each of the slide-contacts cor responding with one of the control members of the receiving apparatus and coupled therewith by means of a second distributing means transmitting signals from the slide-contact members to the receiving apparatus.

Constructing a distribution panel in accordance with the invention results in a reduction in construction costs, while at the same time, provides a means for simple manipulation of the slide members along the contact strips for selectively paralleling individual control members of the receiving apparatus, or, if desired, for connecting particular control members with predetermined sensing members of the program carrier scanning device.

For compactness and ease of construction, the contact strips are arranged longitudinally parallel on a carrier plate comprising a printed circuit board which connects the signals received from the first distributing means to the contact strips. The printed circuit conductor paths correspond in number with the fixed contacts of the contact strips and have contact connecting portions corresponding to the position of the fixed con tacts on the board. Inasmuch as each of the contact strips are provided with identical signals for respective fixed contacts, the printed circuit board approach to distributing these signals to the contact strips results in an economically feasible approach.

A further advantage in using printed circuit boards for distributing signals to the contact strips lies in the ability to provide conductor paths on opposite sides of the carrier plate (i.e., in form of a double sided printed circuit board), the signals being applied to the printed circuit board by means of at least one multi-contact plug connector engaging at least one edge of the printed circuit board. In this manner, in addition to the simple constructive measures realized, rapid exchange of the carrier plates is achievable to provide a variety of interconnect patterns to the contact strips or to provide a convenient means of replacing a damaged board assembly in the event that one of the contact strips is damaged.

A further space-saving construction expedient of the distribution panel assembly lies in the fact that the fixed contacts of the contact strips are formed of a metallic band, one end of which has a contact lug thereon solderable with one of the conductors of the printed circuit board. Each of the fixed contacts is arranged transversely to the longitudinal direction of the contact strips, the contact lug of each fixed contact being oriented 180 from the contact lug of each adjacent fixed contact. Accordingly, the spacing between like ends of the fixed contacts is double the contact-to-contact spacing. In other words, every other fixed contact is oriented in the same direction. Arranging the contact in this manner allows space for the solder drop which connects the contact with the printed circuit board so as to not interfere with adjacent solder drops. Otherwise, the center-to-center spacing of the contacts would necessarily be expanded to permit reliable soldering procedures. Additionally, the spacing between alternate contact soldering lugs achieved by construction in accordance with the present invention permits a printed circuit conductor path to lie therebetween,

thereby improving the contact density of the contact strips.

In the preferred embodiment of the invention, the slide-contact member includes a housing cap engageable with a longitudinal receiving guide on the contact strip. The housing cap has a lower lip which slidably engages the receiving guide to permit the slide-contact member to be selectively positioned along the contact strip. The upper portion of the housing cap is provided with a handle accessible externally thereof and movable from a first position to a second position to disengage and engage respectively mating fixed contacts and slide-contacts.

The slide-contacts are likewise constructed of a resilient metallic band and arranged on a contact plate of the housing cap transversely to the direction of movement of the slide-contact member. The slide contacts are in the form of wiper contacts bent angularly downward, one end of each wiper contact being affixed to the contact plate and the other end of each wiper contact resiliently biased away from the contact plate. In the second position of the handle the contact plate is lowered in the direction of the contact strip, whereby the resilient wiper contacts are bent back towards the contact plate having a horizontal component of movement, thereby attaining an automatic wiping and cleaning of the mating fixed contact.

A further feature of the invention lies in the capability of producing small contact strip segments in identical form which can be assembled end-to-end to comprise an elongated composite contact strip. To aid in the assembly of the contact strip segments, each segment has at least one detent projection and at least one detent recess arranged to be engageable with a corresponding detent recess and detent projection, respectively, of adjacent strip segments. In this manner, the contact strips can be assembled in desired lengths equal to any multiple lengths of the segments. Further, the smaller segments can be produced more economically than a single elongated contact strip, and additionally, the lightness of weight of the individual segments permits the strip segments to be produced from synthetic materials incorporating economical press molding or injection molding methods.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment by way of example of the device in accordance with the present invention is shown in the drawings which illustrate the applicability of the distribution panel to a knitting machine.

In the drawings:

FIG. 1 is a perspective view of a knitting machine, a signal source, and a distribution panel in accordance with the invention;

FIG. 2 is a plan view on an enlarged scale of a fragmentary portion of a contact strip used with the distribution panel according to FIG. 1;

FIG. 3 is a vertical section view taken along the line Ill-III of FIG. 2;

FIG. 4 is a vertical section view taken along the line IV-IV of FIG. 2;

FIG. 5 is a longitudinal section on an enlarged scale of a slide-contact member utilized in the distribution panel according to PK]. 1;

FIG. 6 is a vertical section view taken along the line VI-Vl of FIG. 5; and

- plate used in the apparatus shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, there is shown a knitting machine 2 whose needles and needle carriage may be operated by individual pneumatic or hydraulic driving devices. The

needle drive member operates under the control of control members 4, which in the embodiment shown are combined groupwise in control boxes 6, and are controllable by means of electrical control impulse input signals. The impulse signals originate from a multi-tracked program carrier, for example a sleeve 8 of synthetic material, and are stored according to a predetermined program on the program carrier. Information of the carrier is sensed by a scanning device 10 which may comprise a plurality of impulse-transducers (not shown) to convert the stored program of .the program carrier into electrical impulses to be ultimately transferred to the control members 4. The control members 4 react to the selected electrical impulses to produce a predetermined pattern by the pattern device ofthe knitting machine 2.

The particular arrangement of the various parts of the distribution panel affords the possibility of connecting individual ones of the control members 4 in parallel with at least one further control member 4, or connecting selected ones of the control members 4 to be individually controlled by a particular impulse transducer (not shown) of scanning device 10.

A first distribution means 12 is arranged in a desired I configuration for transmitting selected signals from the scanning device 10 to a carrier plate which serves to supply the selected signals to contact strips 14. In a manner to be described later in further detail, the contact strips 14 are provided with at least one slide-contact member 16 engageable with a receiving guide 28 longitudinally coupled with the contact strip for variably positioning the slide member 16 along the contact strip 14.

As may be gathered by reference to FIG. 1, particularly in view of FIG. 2, each of the contact strips 14 include, in the preferred embodiment two rows of isolated fixed contacts 18 which may take the form of any known contact construction for example, flat strips, elastic metallic bands, or edge-oriented laminated sheets. The fixed contacts 18 of each contact strip 14 are electrically connected in an identical pattern. Ac-

cordingly, corresponding contacts 18 of each contact strip 14 are electrically connected in parallel. Connection between corresponding contacts 18 of adjacent contact strips are provided by means of a carrier plate 20 which incorporates a printed circuit board, part of which is shown on an enlarged scale in FIG. 9.

Signals picked up by the scanning device 10 are routed to the printed circuit board of carrier plate 20 by means of a first distributing means 12 which comprises a plurality of cables 22 connected between the impulse-transducers of the scanning device 10 and the carrier plate 20, connection to the carrier plate 20 being effected by means of multi-contact plug connectors 24. Desired impulse signals are then selected by positioning the slide-contact members 16 along their corresponding contact strips 14, the signals being transmitted to the control members 4 of the knitting machine 2 by means of a second distributing means 26 in the form of a multi-conductor cable.

The contact strips 14 are identical one with the other, both with respect to the number of contacts thereon, and the contact construction. Similarly, the slide-contact members 16 are also identical one with the other. Accordingly, the following description refers to a typical contact strip 14, a partial view of which is shown in FIGS. 2-4, and a typical slide-contact member 16 shown in section view in FIGS. 5 and 6.

Referring in particular to FIGS. 2-4, the contact strip 14 is constructed with a receiving guide 28 in the form of a rail. In the preferred embodiment, the guide is formed by two receiving guide sections 28 for engagement with mating lip sections 30 of the slide-contact I member 16.

The contact strip 14 may consist of strip segments 32 adapted to be assembled as a composite structural unit, each of the sections having a section of receiving guide 28 which are brought into alignment by means of at least one detent projection 34 and at least one detent recess 36 arranged to be engageable with a corresponding detent recess and detent projection, respectively, of adjacent strip segments.

With particular reference to FIG. 3 and 4, it will be seen that the fixed contacts 18 are arranged to lie adjacent the top of a corresponding number of projections 38 of insulating synthetic material. Between each of the fixed contacts 18, there is provided an opening 40 such that each contact 18 is separated from its adjacent contact by a free intermediary space.

In the embodiment shown in the drawings, the contact strip 14 is provided with two rows of fixed contacts 18, between which rows a toothed construction is formed from the insulating material, extending in a longitudinal direction between the two rows. The toothed construction is formed by a series of teeth 42 which lie transversely in a row between the two rows of contacts 18 and are positioned such that the recesses between teeth 42 are latitudinally aligned directly adjacent the edges of opposing contacts 18 in the two rows. As seen in FIG. 3, the height of the teeth 42 is substantially the same as the height of the upper surface of each contact 18, while the lower surface of the recess between the teeth 42 lie in the same plane as the lower surfaces of the intermediary space between fixed contacts 18.

Turning now to FIGS. 5 and 6, a slide-contact member 16 is shown which comprises a housing cap 44 opening in a downwardly directed direction, and which is provided with a lip 30 for engagement with the receiving guide sections 28 of the contact strip 14. The mutually engaging lip 30 and receiving guide sections 28 are constructed in such a manner that the housing cap 44 is slidable in a longitudinal direction of the contact strip 14. However, as particularly viewed in FIG. 4, the housing cap 44 is not removable from engagement with the receiving sections 28 by an upwardly directed force.

Within the housing cap 44, there is arranged a contact plate 46 constructed of insulating material and fitted with wiper contacts 48, one end of which are connected electrically to second distributing means 26. The contact plate 46 is slidably mounted within the housing cap 44 to adjustably position the surface of the contact plate 46 with respect to the open end of housin g cap 44.

The wiper contacts 48 are formed of a resilient metallic band or strip having one end affixed to the contact plate 46, the other end being resiliently biased downwardly and away from contact plate 46. It will be appreciated that the form of wiper contacts 48 shown in the drawing is by way of example only, and that other types of resilient contacting members can be used. For example, elastic means can be provided in the form of a spring to bias the wiper contacts 48 into the angular position shown in FIG. 6.

The spacing interval of wiper contacts 48 on the contact plate 46 correspond with the spacing interval of the stationary fixed contacts 18 of the contact strip 14.

As previously indicated, contact plate 46 is arranged within housing cap 44 to be adjustable in height with respect to the opening end of cap 44, and is pretensioned by means of elastic means, for example compression springs 50, in a lowered position (as viewed in FIGS. and 6). In the lowered position, the wiper contacts 48 engagingly contact fixed contacts 18 of contact strip 14 and are thereby bent or displaced out of the angular position shown in FIG. 6 into a position approximately parallel with contact plate 46.

The contact plate 46 is adjustable within housing cap 44 by means of a handle 52 accessible from the outer side of the housing cap 44. The handle 52 is provided with a cam portion 54 which is rotatably positioned between two bearing strips 56 guided through slits in the housing cap 44 and is supported against the upper side of the housing cap 44. When the handle 52 is swung to a first position as shown in FIG. 5, the contact plate 46 moves upwardly (as viewed in FIG. 5) against the influence of springs 50. In the raised position, (FIG. 7) the wiper contacts 48 are disengaged from the fixed contacts 18, while in the lowered position, (FIG. 8) with the handle in a second position (shown by the arrow 58 in FIG. 5), the wiper contacts 48 contact with the fixed contacts 18 and permit the signals at contacts 18 to be received by wiper contacts 48 and transmitted out of housing cap 44 by means of second distributing means 26.

The contact plate 46 has at least one detent tooth 60 which is positionable between two of the teeth 42 when the contact plate 46 is in a lowered position. To aid in properly centering the fixed and wiper contacts, the detent tooth 60 is tapered at its lowered end and projects downwardly beyond the lowest point on wiper contacts 48. In the embodiment shown in FIG. 6, it will be appreciated that a series of detent teeth 60 are provided, the teeth being formed out of the insulating material of contact plate 46. The series of teeth extend over the entire plate length in the center of its width. The detent tooth 60 or the series of detent teeth 60 cooperate with the teeth 42 of contact strip 14 to allow the slide-contact member 16 to be positionable along the contact strip 14 at incremental distances corresponding to the distance between wiper contacts 48.

The contact plate 46 is further provided with downwardly projecting separating walls 62 disposed between adjacent wiper contacts 48. Separating walls 62 project into the intermediary openings 40 between fixed contacts 18 when the contact plate 46 is in its lowered position. In this manner, an insulating wall is existent between adjacent wiper contacts in the engaged position of slide member 16 with contact strip 14. Such an arrangement as seen in FIG. 8 insures adequate protection against a wiper contact sliding into an adjacent intermediary opening 40.

In order to provide the operator of the distribution panel with a reasonable expectancy of making accurately aligned contact engagement with the contact strip 14, identifying marks 64 are provided on the side rims of the contact strip 14, while a projecting stud 68 is provided on slide member 16, thereby permitting accurate and predictable engagement of the slidemember 16 with the contact strip 14 when the stud 68 is aligned with one of the identifying marks 64.

FIG. 9 shows a printed circuit board arranged underneath the carrier plate 20, whose printed circuit conductor paths connect corresponding ones of fixed contacts 18 of adjacent contact strips 14. A multi-contact plug connector 70 engages with opposite edges of the printed circuit board to provide connection to all of the fixed contacts 18 with signals from the scanning device 10. A study of FIG. 9 will show that connector plugs 70 are provided at opposite ends of the printed circuit board so that interlacing of the signal conductors to attain extremely high contact density is possible. It is contemplated that in order to provide proper conductor path density on the printed circuit board, the conductors may be arranged on opposite sides of carrier plate 20 such that half the number of conductor imprints on the printed circuit board connect with half of the fixed contacts 18, while the remaining conductor imprints connect with the other half of fixed contacts 18.

The manner in which the fixed contacts 18 are soldered to the printed circuit board conductor paths can be inferred by reference to FIGS. 3 and 4. With particular reference to FIG. 4, it will be noted that the band-shaped fixed contacts 18 are provided on one end with a soldering lug 72, capable of being passed through bores in the contact strips 14 as well as of the carrier plate 20. It can also be inferred by reference to FIGS. 3 and 4 that the arrangement of the fixed contacts 18 is such that the soldering lug 72 of adjacent fixed contacts in each row of contacts are offset one from the other by The ends of the band-shaped fixed contacts 18 lying opposite the solder lugs 72 are (by reference to FIG. 4) bent laterally outward and positioned below corresponding portions of contact strip 14 to thereby secure the contact 18 against its supporting projection 38.

Due to the offset arrangement of adjacent fixed contacts 18, the distance between adjacent soldering lugs 72 (reference FIG. 9) is great enough that between the soldering lugs, in spite of enlarged soldering drops connecting the lugs to the printed circuit board, a sufficiently large space remains in order to pass through at least one additional conductor imprint.

The above description deals with the present invention in connection with distribution of impulse signals to control the control elements of a knitting machine. It should be realized, however, that the invention is useful in a variety of other applications as a distributor device, and constructional details deviating from the specific embodiment of the invention disclosed herein is anticipated. The specific embodiment of the invention described herein was chosen so that those skilled in the art may understand the manner of practicing the basic distribution panel, and the scope of the invention will be understood to be limited only by the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An electrical circuit selection device for determining the routing of electrical signals, comprising a base member, at least one row of fixed contacts carried by said base member in uniformly spaced arrangement, a guide rail mounted on said base member, extending parallel and adjacent to said row of contacts, a housing slidably guided by said rail and extending over some of the contacts in said row, a contact plate of insulating material in said housing, wiper contacts carried by said plate, said wiper contacts being uniformly spaced at the same interval as said fixed contacts, means in said housing adapted to lower said contact plate until said wiper contacts are in electrical engagement with a corresponding number of said fixed contacts or to raise it until they are out of electrical engagement, detent teeth of insulating material extending from said contact plate in a direction toward said fixed contacts, and a row of recesses in said base, adapted to receive said teeth, and so arranged that said teeth will engage said base and prevent lowering of said contact plate except when said wiper contacts are in alignment with a corresponding number of said fixed contacts, as determined by said teeth being in alignment with said recesses.

2. The device as claimed in claim 1, wherein: said housing carries a handle accessible externally of said housing cap and movable from a first position to a second position to actuate said means in said housing,

said wiper contacts being out of engagement with said fixed contacts in said first position and in engagement therewith in said second position.

3. The device as claimed in claim 1, wherein each of said wiper contacts is formed of a resilient metallic band and arranged on said contact plate transversely to the direction of travel of said housing along said guide rail, said wiper contacts being bent angularly downward, one end of each wiper contact being affixed to said contact plate and the other end of each wiper contact resiliently biased away from said contact plate.

4. The device as claimed in claim 2 wherein said contact plate is pretensioned by elastic means in a direction toward said fixed contacts and movable towards and away from said fixed contacts when said handle is in said second and first positions respectively, said handle including a cam portion and said housing having a cam surface for effectuating movement of said contact plate.

5. The device as claim in claim 1, wherein said base member is constructed of a plurality of identical contact strip segments, each of said strip segments comprising a segment of guide rail and a group of fixed contacts, and adapted to be aligned side-by-side with similar segments to form an extended row of fixed contacts with adjacent guide rail.

. The device as claimed 1n claim 5, wherein each of said contact strip segments has at least one detent projection and at least one detent recess arranged to be engageable with a corresponding detent recess and detent projection respectively of adjacent strip segments.

7. The device as claimed in claim 1, wherein said base member has elongated openings between said fixed contacts, and said contact plate includes separating walls between wiper contacts, said walls arranged to mate with corresponding openings when said contact plate is positioned to engage said wiper contacts with said fixed contacts, said walls thus providing an insulating barrier between adjacent pairs of fixed and wiper contacts. 

1. An electrical circuit selection device for determining the routing of electrical signals, comprising a base member, at least one row of fixed contacts carried by said base member in uniformly spaced arrangement, a guide rail mounted on said base member, extending parallel and adjacent to said row of contacts, a housing slidably guided by said rail and extending over some of the contacts in said row, a contact plate of insulating material in said housing, wiper contacts carried by said plate, said wiper contacts being uniformly spaced at the same interval as said fixed contacts, means in said housing adapted to lower said contact plate until said wiper contacts are in electrical engagement with a corresponding number of said fixed contacts or to raise it until they are out of electrical engagement, detent teeth of insulating material extending from said contact plate in a direction toward said fixed contacts, and a row of recesses in said base, adapted to receive said teeth, and so arranged that said teeth will engage said base and prevent lowering of said contact plate except when said wiper contacts are in alignment with a corresponding number of said fixed contacts, as determined by said teeth being in alignment with said recesses.
 2. The device as claimed in claim 1, wherein: said housing carries a handle accessible externally of said housing cap and movable from a first position to a second position to actuate said means in said housing, said wiper contacts being out of engagement with said fixed contacts in said first position and in engagement therewith in said second position.
 3. The device as claimed in claim 1, wherein each of said wiper contacts is formed of a resilient metallic band and arranged on said contact plate transversely to the direction of travel of said housing along said guide rail, said wiper contacts being bent angularly downward, one end of each wiper contact being affixed to said contact plate and the other end of each wiper contact resiliently biased away from said contact plate.
 4. The device as claimed in claim 2 wherein said contact plate is pretensioned by elastic means in a direction toward said fixed contacts and movable towards and away from said fixed contacts when said handle is in said second and first positions respectively, said handle including a cam portion and said housing having a cam surface for effectuating movement of said contact plate.
 5. The device as claim in claim 1, wherein said base member is constructed of a plurality of identical contact strip segments, each of said strip segments comprising a segment of guide rail and a group of fixed contacts, and adapted to be aligned side-by-side with similar segments to form an extended row of fixed contacts with adjacent guide rail.
 6. The device as claimed in claim 5, wherein each of said contact strip segments has at least one detent projection and at least one detent recess arranged to be engageable with a corresponding detent recess and detent projection respectively of adjacent strip segments.
 7. The device as claimed in claim 1, wherein said base member has elongated openings between said fixed contaCts, and said contact plate includes separating walls between wiper contacts, said walls arranged to mate with corresponding openings when said contact plate is positioned to engage said wiper contacts with said fixed contacts, said walls thus providing an insulating barrier between adjacent pairs of fixed and wiper contacts. 